Vision 2

where the signals from vision 1 go

All sensory systems tend to project through the what?

thalamus

What specific part of the thalamus does vision go through?

lateral geniculate nucleus (LGN)

What is the flow of information from the eyes to the brain?

1) eyes

2) retinal ganglion cell

3) optic nerve
4) optic chiasm

5) left/right brain hemisphere

6) LGN

7) visual cortex

The brain does not care about the left/right eye, it cares about what?

left/right visual fields

Something in the right visual field has to get put together in ____ side of the brain.

1

The right (or left) portion of your visual space is processed by ______ eye(s).

both

What is the purpose of the optic chiasm?

the crossing of some of the optic and visual information

What does it mean when a region of visual space is binocular?

it is heavily processed by both eyes

The lateral ganglion nucleus is a _________ structure.

layered

Information is ___________ from which eye its coming from?

segregated by later

What does contralateral mean?

opposite side

What does ipsilateral mean?

same side

How are the layers of the LGN organized/what do they process?

3 layers process contralateral info

3 layers process ipsilateral info

Projections from retina to LGN are ____________ organized.

retinotopically

LGN neurons all have ______________ identical to ganglion cells.

circular receptive fields

Where does the information from the LGN go to?

primary visual cortex

The cortex is what?

a layered structure

What do the layers in the primary visual cortex do?

provide inputs and send outputs

What layer do the inputs from the LGN go to in the visual cortex?

4C

What does layer 4C do in the visual cortex?

serves as the input layer and sends inputs to different parts of the visual cortex

4C cells are also known as what?

stellate cells

What do stellate cells have in common with the LGN and ganglion cells?

they all have circular receptive fields

What is V1?

primary visual cortex

Who mapped out how vision works in the terms of cell structure and the way they respond?

David Hubel and Torsten Wiesel

What did David Hubel and Torsten Wiesel do? (what was their experiment)

placed microelectrodes into the visual cortex of a cat looking at a screen to record APs from individual neurons

What do simple cells respond to?

bars of light across the receptive field (in specific orientations)

What happens if you shine a bar of light across the entirety of the off region?

you get the off response (like the retinal ganglion cells)

What happens if you shine a bar of light across the entirety of the on region?

you get the on response (like the retinal ganglion cells)

Simple cells have an elongated receptive field with what?

an on region flanked by an off region

What happens when the bar of light covers the entire receptive field of a simple cell?

no response

What happens when a bar of light of varying orientation covers part of the receptive field?

weak response

The more aligned the bar of light is with the plus (on) receptive field in simple cells, the more what?

the stronger the response

Cells within the same column of the visual cortex tend to have what?

similar tuning

Cells across columns of the visual cortex tend to have what?

variations in tuning

Ganglion cells in the retina and LGN are not senstitive to what?

the orientation of the bar of light

vision pt 2

slide 101

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